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Topic:Age Factors
Age factors in horses encompass a range of physiological and developmental changes that occur as horses mature from foals to adults and eventually into their senior years. These factors include variations in metabolic rate, immune function, and musculoskeletal development, which can influence a horse's health, performance, and nutritional needs. Age-related changes can also affect how horses respond to medications, recover from injuries, and maintain overall vitality. Researchers study these aspects to understand better how age impacts equine health and management. This page compiles peer-reviewed research studies and scholarly articles that explore the effects of age on equine physiology, health management, and disease susceptibility.
Pathological studies of cheek teeth apical infections in the horse: 2. Quantitative measurements in normal equine dentine. Measurements of primary, regular and irregular secondary dentine and pulp dimensions were made on transverse, sub-occlusal and mid-tooth sections, of 40 maxillary and 42 mandibular control equine cheek teeth (CT) of different ages. Maxillary and mandibular CT primary dentine in different age groups had a mean thickness of 922-1,065 microm and 1099-1,179 microm, respectively, on the lateral aspects, and 1,574-2,035 microm and 1155-1,330 microm, respectively, on the medial aspects of pulp horns. Surprisingly, some increase in thickness was found in some mandibular CT primary enamel in the first ...
Evaluation of risk factors, management, and outcome associated with rectal tears in horses: 99 cases (1985-2006). To identify risk factors for rectal tears in horses; assess the effect of initiating cause on tear location, size, and distance from anus; and determine short-term survival rate among horses with various grades of rectal tears. Methods: Retrospective case series. Methods: 99 horses. Methods: Medical records for horses with a rectal tear were reviewed, and data including age; sex; breed; cause, location, and size of the tear and its distance from the anus; tear grade; treatment; and outcome (short-term survival [ie, survival to discharge from the hospital] vs non-survival) were recorded. Data f...
Effects of age on follicle and hormone dynamics during the oestrous cycle in mares. The effects of age (young: 5-6 years; intermediate: 10-14 years; old: > or =18 years) on follicle and hormone dynamics during an interovulatory interval (IOI; n = 46) and on preovulatory oocytes and concentrations of follicular fluid factors (n = 44) were studied in mares. Old mares were not approaching senescence, as indicated by regular lengths of the IOI (19-27 days) during the period May-October. The IOI was 1 day longer (P < 0.05) in the old group than in the two younger groups and was associated with a slower (P < 0.05) growth rate of the ovulatory follicle. The old group had di...
Vegetative endocarditis in equids (1994–2006). Endocarditis is a rare heart condition with variable clinical expressions in equids. Risk factors for this disease are incompletely understood. Objective: Describe risk factors for endocarditis in equids. Methods: One hundred and fifty-three equids admitted to Liège University, 9 diagnosed with endocarditis and 144 free from endocarditis but admitted to the hospital with a differential diagnosis including this disease. Methods: Retrospective case-control study. Results: Equids with endocarditis were significantly younger (mean age = 4.84 +/- 5.74 years) than control equids (mean age = 10.8 +/...
Age-related dynamics of follicles and hormones during an induced ovulatory follicular wave in mares. An ovulatory follicular wave was induced by ablation of follicles > or =6mm and treatment with prostaglandin F2alpha (PGF) on Day 10 (ovulation=Day 0). Follicle and hormone dynamics of the induced waves were compared among three age groups: young (5-6 y, n=14 waves), intermediate (10-14 y, n=16), and old (> or =18, n=15). During the common-growth phase of the induced wave (Days 12-17), diameter of the future ovulatory follicle was not different among ages, but the young group had more (P or =10mm. The number was correlated (r=+0.7; P<0.0001) within mares between consecutive interovula...
Factors affecting foal birth weight in Thoroughbred horses. Foaling data from 348 Thoroughbred foals born on a commercial stud were analysed to investigate interrelationships among mare age, parity, gestation length, foal sex, placental weight, and foal birth weight. Placental weight was positively correlated with foal birth weight up to a threshold of 6.5 kg; above this, placental weight was not significantly associated with foal birth weight. Placental weight was assessed, including the amniotic membranes and umbilical cord as well as the allantochorion. Using path analysis, parity was positively associated with foal birth weight both directly and th...
Associations of sex, breed, and age with cervical vertebral compressive myelopathy in horses: 811 cases (1974-2007). To determine sex, breed, and age distributions in a population of horses with cervical vertebral compressive myelopathy (CVCM), compared with contemporaneous control horses. Methods: Retrospective case-control study. Methods: 811 horses with CVCM and 805 control horses. Methods: The Veterinary Medical Database was searched to identify horses with CVCM and contemporaneous control horses registered between July 1974 and August 2007. Admission date, admitting institution, sex, breed, age at the time of registration in the database, weight, and discharge status (alive, died, or euthanized) were re...
Profiling training preparation in young Australian Thoroughbred racehorses. To describe the impact of age, sex, and musculoskeletal (MS) injury on three preparation-level measures of performance: (i) the duration of preparation, (ii) time from the beginning of the preparation until the first start in a race or barrier trial, and (iii) time from the first start until the end of the preparation. Methods: Daily training and injury data for 2- and 3-year old Thoroughbred racehorses were collected fortnightly from 14 trainers in NSW, Australia. Training data were aggregated into units referred to as 'preparations'. Univariate and multivariate analytical methods were used t...
Effect of body condition, body weight and adiposity on inflammatory cytokine responses in old horses. Advanced age is associated with a low-grade, systemic inflammatory response characterized by increased inflammatory cytokine production both in vitro and in vivo, termed inflamm-aging. It is also known that increased white adipose tissue, associated with obesity, leads to increased production of inflammatory cytokines. To date, it is unknown whether increased adiposity contributes to the age-related increased inflammatory status. Here we show that peripheral blood mononuclear cells (PBMC) from old horses compared to young horses have increased inflammatory cytokine production; moreover, fat ol...
[Toward exploration of morphological disparity of measurable traits of mammalian skull. 1. Interrelation between different forms of group variation]. Interrelations between some forms of group variation (FGVs) (age, sex, geographic, inter-species, differences among breeds) of 12 to 15 measurable skull traits are studied in 6 mammal species (pine marten, polar fox, Przewalskii horse, and 3 jird species) by means of dispersion analysis (model III, MANOVA). The above FGVs are considered as factors in the MANOVA, and skull traits are considered as dependent variables. To obtaine commeasurables estimates for the FGVs, each of them is assessed numerically as a portion of its dispersion in the entire morphological disparity defined for each charac...
Age-related changes in cytokine expression by neutrophils of foals stimulated with virulent Rhodococcus equi in vitro. Although evidence exists that neutrophils play a vital role in resistance to infection with Rhodococcus equi, the means by which neutrophils exert their effects have not been clearly defined. In the present study we evaluated differences in cytokine expression by unstimulated and R. equi-stimulated neutrophils obtained from newborn foals and subsequently at 2-, 4-, and 8-weeks of age. Stimulation with virulent R. equi induced significantly (P<0.05) greater expression of IFNgamma, TNFalpha, IL-6, IL-8, IL-12p40, IL-12p35, and IL-23p19 mRNA relative to expression by unstimulated neutrophils, ...
Advanced age in horses affects divisional history of T cells and inflammatory cytokine production. A number of model systems have been employed to investigate age-associated changes in immune function. The purpose of the current study was to characterize senescent T cells and to investigate the inflamm-aging phenomenon both in vitro and in vivo using the old horse as a model. We examined whether decreased T cell proliferation induced by Con A is caused by increased apoptosis. We also utilized intracellular CFSE to analyze changes within each round of cell proliferation, in particular cytokine production. Intracellular staining with flow cytometry, RT-PCR, and ELISA were used to measure pro-...
Activation of peripheral blood monocytes results in more robust production of IL-10 in neonatal foals compared to adult horses. Foals are particularly vulnerable to infection by Rhodococcus equi during the first 2 weeks of life whereas mature horses are not. While an innate immunodeficiency likely accounts for this clinically relevant vulnerability, the factors that contribute to infection by R. equi have not been fully elucidated. In this study, we demonstrate that cells of the monocyte lineage, including monocytes, macrophages, and dendritic cells, that have been activated with LPS and IFN-gamma, respond with a statistically significant, greater amount of cytokine mRNA production of IL-10, IL-12p35, and IL-12p40 than...
[Horses in Switzerland: results of a representative survey of population, housing and use in 2004]. A survey of 2559 stables, representative for Switzerland, was conducted in the year 2004, with questions related to age, sex, breed, housing conditions, social contact, use, feeding, ability to move freely on the one hand, and health prophylaxis and health disorders in the past 12 months on the other. With a respond rate of 30.9% to the questionnaire, data for 2912 horses and ponies were recorded. The data were compared to a previous survey of 1997 (Bachmann & Stauffacher, 2002). In this study, data on population, housing and use were analysed. The proportion of horses kept individually, e...
Chronobiologic blood pressure assessment: maturation of the daily rhythm in newborn foals. Circadian rhythmicity of physiological processes in animals has been described for some variables. In order to investigate the daily rhythmicity of blood pressure, seven foals (Equus caballus) were used for 40 days after birth. Measurements of blood pressure were done by means of an oscillometric apparatus (Argus TM-7, Schiller, Barr Switzerland) with the foals in a standing position and the cuff placed around the tail. Blood pressure was recorded twice a day, 1 hour before dawn and 1 hour before dusk for the first 10 days of life, every 2 days from the 11th to the 32nd day, on the 36th and on...
The demographics of equestrian-related injuries in the United States: injury patterns, orthopedic specific injuries, and avenues for injury prevention. It was the purpose of this study to review equestrian-related injuries using a large nation wide database and analyze predictors of significant injury. Methods: The National Electronic Surveillance System database was queried for equestrian injuries from 2002 to 2004. The presence of a fracture, dislocation, traumatic brain injury, musculoskeletal injury, orthopedic injury, and spinal injury, as well as injury mechanism, geographical location, and emergency room disposition were noted. Bivariate, cosinor seasonal, and multiple logistic regression analyses were performed. p 18 years, traumatic ...
Analysis of horse-related injuries in children. The purpose of the present study was to investigate factors affecting the nature, characteristics, severity and outcome of horseback and horse care injuries in paediatric patients and to create guidelines for injury prevention. Methods: Detailed clinical records of 265 children sustained horse-riding related injuries have been analysed. Questionnaires were mailed to provide follow-up information for patients who have been treated in either Department of Paediatric Surgery in Pécs, Hungary, or Department of Paediatric Surgery in Graz, Austria between 1999 and 2003. Those 112 children (42%) who...
Fat content and fatty acids profile of colostrum and milk of primitive Konik horses ( Equus caballus gmelini Ant.) during six months of lactation. The effect of the stage of lactation, the number of foals and age of the mare on changes in the fat content and fatty acid composition of colostrum and milk of primitive Konik horses was investigated. Colostrum and milk samples from 12 lactating mares were collected at the beginning of lactation, on the days 1 and 2 after foaling and then, starting from the first month of lactation, at 4-week intervals up to the sixth month of lactation. Significant differences were observed in fat content as well as the composition of some analysed fatty acids between colostrum and milk of mares of the Konik ...
Plasma vasopressin concentrations in healthy foals from birth to 3 months of age. Arginine vasopressin (AVP) has received increased attention in equine critical care but there is minimal information of AVP concentration in foals. The clinical usefulness of measuring AVP in ill foals depends on knowledge of age-related changes in AVP concentrations in healthy foals. Objective: Plasma AVP concentrations will be significantly different when measured from birth to 3 months of age in healthy foals. Methods: Thirteen healthy university-owned foals. Methods: Prospective, observational study. Blood was collected from healthy foals at birth and 3, 5, 7, 10, 14, 21, 28, 42, 56, and 8...
Follicle development in mares. The mare provides a unique experimental model for studying follicle development in monovular species. Development of antral follicles in horses is characterized by the periodic growth of follicular waves which often involve the selection of a single dominant follicle. If properly stimulated, the dominant follicle will complete development and eventually ovulate a fertile oocyte. Regulation of follicular wave emergence and follicle selection involves an interplay between circulating gonadotropins and follicular factors that ensures that individual follicles are properly stimulated to grow (or t...
Identification of factors associated with the development of insect bite hypersensitivity in horses in The Netherlands. An Internet-based questionnaire among horse owners was carried out to identify factors affecting the incidence of insect bite hypersensitivity (IBHI) among horses in the Netherlands. Information was obtained for 794 horses of various breeds, but the breed distribution was not representative for the Dutch horse population. Of the horses for which information was available, 56% suffered from IBH and 44% did not. The most common clinical symptoms were pruritus, scaling, and hair loss, occurring mainly at the base of the tail and along the mane. Breed, age, region (and local habitat), stabling, ty...
Demographics and costs of colic in Swedish horses. Colic is an important cause of morbidity and mortality in horses. In Sweden, an insurance database with diagnostic medical information is maintained on >30% of the nation's horse population. Objective: The objective was to describe the occurrence of colic, defined by costly veterinary care and life claims, in horses at 1 insurance company during 1997-2002. HORSES: All horses (<21 years of age) with complete insurance for veterinary care and life during the period 1997-2002 were included. Methods: Colic was defined as conditions where the main clinical sign was abdominal pain and the prob...
The effect of age and telomere length on immune function in the horse. Telomeres, specialized structures present at the ends of linear eukaryotic chromosomes, function to maintain chromosome stability and integrity. Telomeres shorten with each cell division eventually leading to replicative senescence, a process thought to be associated with age-related decline in immune function. We hypothesized that shortened PBMC telomere length is a factor contributing to immunosenescence of the aged horse. Telomere length was assessed in 19 horses ranging in age from 1 to 25 years. Mitogen-induced 3H-thymidine incorporation, total serum IgG, and pro-inflammatory cytokine exp...
Equine-related facial fractures. Horseback riding is a common recreational activity that can cause injuries to both mounted and dismounted participants. This study examines the patterns of equine-related maxillofacial fractures presenting in a tertiary referral centre. Patients presenting over an 11-year period from 1996 to 2006 with equine-related maxillofacial fractures were identified through the trauma database. The extent of the injuries, surgical treatment and follow-up details were documented. 45 patients were identified, with an increasing incidence over the study period. 69% were male and 31% female. 31% of patients ...
Helicobacter equorum is highly prevalent in foals. Faecal samples of sixty-six 3-day- to 6-month-old foals were screened for Helicobacter equorum DNA by means of a PCR amplifying a 1074 bp fragment of the 23S rRNA gene with primers specific for this enterohepatic Helicobacter species. H. equorum DNA was demonstrated in faeces from 28.6% of the less than 1-month-old foals, while 67.8% of foals from 1 to 6 months of age tested positive. In a previous study, H. equorum was demonstrated in faeces of 0.8-7.9% of adult horses. These results indicate that the prevalence of H. equorum in horses differs with the age of the investigated horse population...
Seasonal changes in circadian peripheral plasma concentrations of melatonin, serotonin, dopamine and cortisol in aged horses with Cushing’s disease under natural photoperiod. Equine pituitary pars intermedia dysfunction (PPID) is a common and serious condition that gives rise to Cushing's disease. In the older horse, it results in hyperadrenocorticism and disrupted energy metabolism, the severity of which varies with the time of year. To gain insight into the mechanism of its pathogenesis, 24-h profiles for peripheral plasma melatonin, serotonin, dopamine and cortisol concentrations were determined at the winter and summer solstices, and the autumn and spring equinoxes in six horses diagnosed with Cushing's disease and six matched controls. The nocturnal rises in p...
Clinical and scintigraphic findings in horses with a bone fragility disorder: 16 cases (1980-2006). To describe clinical and scintigraphic abnormalities in horses with a bone fragility disorder. Methods: Retrospective case series. Methods: 16 horses with scintigraphic evidence of multiple sites of increased radiopharmaceutical uptake (IRU). Procedures-Medical records were reviewed for information on signalment; history; clinical, clinicopathologic, and diagnostic imaging findings; and treatment. Follow-up information was obtained through telephone interviews with owners. Results: Horses ranged from 4 to 22 years old; there were 8 castrated males and 8 females. Foci of IRU most commonly invol...
Transvaginal ultrasound-guided aspiration of unilateral twin gestation in the mare. Embryo reduction of unilateral twin vesicles is normally successful before fixation of the vesicles. After fixation, however, it becomes a challenge, and the later in the gestation period that the reduction is performed, the greater the challenge. One therapy to reduce a twin into a singleton pregnancy is the transvaginal ultrasound-guided aspiration (TUGA) of one of the vesicles. The results of 35 unilateral twin reductions by TUGA are discussed in this paper and possible negative influences of age, parity and days pregnant are analysed statistically.
Penile and preputial tumours in the horse: a retrospective study of 114 affected horses. Preputial and penile tumours are more common in horses than in other domestic animals, but no large surveys of male horses with tumours of the external genitalia are available. Objective: To present a retrospective analysis of male horses with neoplasms of the external genitalia. Methods: The penile and preputial tumours of 114 horses were evaluated. Data recorded included age, gelding or stallion and breed; type and site of lesion; involvement of regional lymph nodes; histopathology (including grading of squamous cell carcinoma); and results of radiographic examination of the thorax. Results:...
Concentrations of ionized and total magnesium and calcium in healthy horses: effects of age, pregnancy, lactation, pH and sample type. Magnesium (Mg) and calcium (Ca) are the main divalent cations in the body. The free ionized fraction is the physiologically active form of both Mg and Ca. As ion-selective-electrode (ISE) analyzers are becoming widely used in veterinary practice it will be useful to establish reference intervals for horses. In the present study, reference intervals were established for ionized, total and the ratio of the ionized to total Mg and Ca concentrations in four horse groups: adults, neonatal foals, and pregnant and lactating mares, as well as in three sample types, whole blood, plasma and serum, using...
